1. Field of the Invention
The present invention relates to an inverter transformer to light a discharge lamp used as a light source of a backlight device for a liquid crystal display device, and more particularly to an inverter transformer provided with a plurality of outputs and adapted to light a plurality of discharge lamps.
2. Description of the Related Art
Since liquid crystal of a liquid crystal display (LCD) device used for, for example, a television, a personal computer, and the like does not emit light by itself, a lighting device, such as a backlight device, is required. The backlight device employs as its light source a discharge lamp, typically, such as a cold cathode fluorescent lamp (CCFL). Recently, the LCD device is becoming larger and larger and also a higher brightness is required for use in, for example, an LCD television, and therefore the backlight device incorporates a plurality of CCFLs as its light source. A high voltage required to light a CCFL is produced such that a high frequency voltage generated at a switching of an inverter circuit is stepped up by an inverter transformer.
An inverter transformer generally includes a bobbin having primary and secondary windings wound therearound and a core having legs to be inserted in the hollow of the bobbin, and the primary and secondary windings are connected to an outside circuit disposed at a print circuit board, or the like via terminal pins implanted in the bobbin. In such the inverter transformer, the terminal pin is often bent and formed in an L shape or a square U shape such that lead-out wires of the windings are tied around one bar of the L or square U shape while another bar is fixedly attached to the printed circuit board, to thereby prevent breakage of the wires (refer to, for example, Japanese Patent Application Laid-Open No. 2006-303304, FIGS. 1 to 3 therein).
In the inverter transformer described above, the bar of the terminal pin having the winding wires tied therearound protrudes from the end face of the bobbin and is likely to be subjected to external stresses thus causing a winding breakage problem. This problem is serious particularly with the secondary winding wires which have a smaller diameter than the primary winding wires.